Little is known regarding how conditions during pregnancy and early life may impact epigenetic alterations and aging processes that could subsequently manifest in midlife as atherosclerosis, type 2 diabetes, adiposity and cognitive decline. In particular, there are sizeable and important knowledge gaps regarding associations of prenatal conditions (e.g. intrauterine growth restriction, maternal serum cortisol levels, maternal smoking and socioeconomic adversity) with epigenetic processes (often measured as DNA methylation) that could alter gene expression and disease outcomes. Our goal is to assess aging processes in 3000 of the Collaborative Perinatal Project (CPP) participants born in 1959-1966 who had detailed prenatal assessments, biosample collection and phenotypic assessments during the first 8 years of life. Specific analytic objectives include: (a) to investigate if DNA methylation in subcutaneous adipocytes is associated with measures of adiposity derived from DEXA scans, CT lumbar region scans (to assess visceral fat), waist circumference and BMI;(b) to identify whether prenatal conditions are associated with adiposity and relevant DNA methylation patterns;(c) to evaluate whether DNA methylation in umbilical cord serum is associated with adiposity at ages 0, 4, 7 years and middle age;(d) to investigate whether prenatal conditions are associated with adiposity-related DNA methylation in umbilical cord serum. The study will recruit 3000 CPP participants from Rhode Island and Massachusetts. Sibling sets discordant for intrauterine growth restriction will be oversampled, with a goal of obtaining 500 sibling sets. Clinical assessments include adiposity, atherosclerosis (coronary artery calcium CT scans), cognitive function, diabetes (fasting glucose), and cardiovascular risk factors (e.g. lipids). Subcutaneous adipocyte biopsies and buccal cell collection will be performed. Maternal cortisol levels during pregnancy (approximately 50 years ago) will be measured from banked serum samples. Umbilical cord serum DNA and adipocyte DNA will be obtained using established protocols, and run through deep sequencing DNA methylation assays as biomarkers of epigenetic characteristics. The analytic approach will include a locus-by- locus analysis for each 26,486 autosomal CpG, assessing the association of average methylation with a) adiposity, and b) prenatal/early life risk conditions, correcting for false discovery rate. Within-sibling analyses will be performed to account for shared family and environment as potential confounders. This study offers to provide innovative information to advance understanding of how epigenetic processes are involved in aging, and how perinatal and early life factors may be important determinants of aging. It is one of the very few data sources available worldwide regarding prenatal, early life and middle-age determinants of health. This study offers potential to make major inroads towards understanding modifiable determinants of aging across the lifecourse, beginning during prenatal and early years of life. This could serve to expand the complement of public health strategies that may enhance healthy aging and prevent disease outcomes. PUBLIC HEALTH RELEVANCE: The search for modifiable influences on healthy aging and aging-related disease has led to considerable interest in the potential health impact of conditions during pregnancy and early childhood (e.g. intrauterine grown restriction, maternal smoking, maternal stress during pregnancy, economic distress, maternal cognitive function, childhood cognitive function, childhood blood pressure, childhood body growth and obesity, childhood neglect and maternal mental health). Such information may contribute to critical and effective new alternatives to enhance healthy aging and prevent later disease, by public health interventions early in life. This project will add to the scientific understanding of biological mechanisms by which prenatal and early life factors may influence health, including the potential discovery of biomarkers as targets for treatment and prevention efforts. Overall, this study is one of the very few available sources of prenatal, early life and middle-aged health determinants and health outcomes worldwide, and offers the potential to make major inroads in more fully understanding prenatal and early life determinants of health.